This research project aims at developing signal processing tools for extracting relevant tissue microstructure information embedded in the spectra of rf broadband ultrasonic echoes. The ultimate goal is to provide fast and reliable signal processing techniques for extracting ultrasonic tissue parameters related to the presence of malignant neoplasms. A unique aspect of this project is its focus on characterizing Fourier phase and magnitude of rf ultrasonic tissue echoes with spectral redundancy. Characterization features based on high resolution information will be incorporated into detection algorithms for applications to rf B-scans. In addition, this project considers representations for local high-resolution information to enable doctors and clinicians to make both qualitative and quantitative conclusions about tissue microstructure. Analytical, experimental, and simulation methods will be carried out to study and demonstrate the capabilities of spectral redundancy in characterizing pathological changes in tissue. Experimental data obtained through the clinical core will aid in providing relevant diagnostic information and assessment of the signal processing methods. The success of the proposed research will advance the utility of ultrasound as a low-cost, safe and non-invasive method for the early detection and characterization of malignant tissue.